Looking at the array of ignorant and vindictive old men attacking Greta Thunberg and other young climate activists, the case for lowering the voting age is just about unanswerable. Anything that could be urged in justification of stopping 16 year olds, as a group, from voting, is equally applicable to those over 60 (a group to which I belong). Over 60 voters are, on average, poorly educated (the school leaving age in Australia was 15 when they went through and I assume similar in most places), and more likely to hold a wide range of false beliefs (notably in relation to climate change).
Worse, as voters the over 60s have ceased to act, if they ever did, as wise elders seeking the best for the future. Rather (on average) they vote in a frivolous and irresponsible way, forming the support base for loudmouthed bigots and clowns like Trump, Johnson and, in Australia, Pauline Hanson (the last of whom, unsurprisingly, supports an increase in the voting age). Substantively, they respond to unrealistic appeals to nostalgia, wanting to Make America Great Again, and restore the glories of the British Empire, while dismissing concerns about the future. If my age cohort were to be assessed on the criteria applied to 16 year olds, we would be disenfranchised en masse.
Of course, we can’t do that kind of thing in a democracy,. That’s why we should act consistently with the core democratic principle that those affected by a decision should have a say in making it, unless they are absolutely disqualified in some way. In my view, that makes an open-and-shut case for lowering the voting age to 16.
But where should we stop? If we set the bar at the level of emotional maturity and intelligence shown by say, the crowd at a Trump rally, most 12 year olds would clear it with ease.
So, how about giving everyone a vote? For young children, that would amount to giving parents an extra vote, though it’s worth noting that opponents of womens’ suffrage made the same claim about husbands. In any case, the assumption that parents would vote in their children’s interest seems much more defensible than the idea that the old, as a group, will vote unselfishly about decisions (Brexit, for example, or wartime conscription) that will have little effect on them, but drastic consequences for the young.
More importantly, the age at which young people stop doing as their parents tell them is well below 18. Allowing them to engage directly in the democratic process would be an unambiguously good thing, whether or not they chose more wisely than their elders.